1. Field of the Invention
The present invention relates to a damper disk used as clutch disks for automobiles and others, and particularly to a damper disk including a spring adapted to elastically and axially deflect for absorbing or damping vibration of rotational torque.
2. Description of the Prior Art
The damper disk of the type described above can generally have a large relative torsion angle between an input and output parts or members, and thus can effectively absorb the torque vibration as compared with conventional structures in which springs for absorbing the torque vibration are compressed in a circumferential direction of the disk.
Examples of the disks including such axially deflectable spring are disclosed in the Japanese Utility Model application No. 58-89711 (Laid-Open Publication No. 59-194638) and Japanese Patent Application No. 61-152290, which are commonly assigned to Kabushiki Kaisha Daikin Seisakusho, assignee of the present application.
The disk according to the former application comprises a helical spline as means for converting a relative rotational movement between an input and output parts into an axial movement. This helical spline requires complicated machining work.
The disk according to the latter application can dissolve such a disadvantages. It comprises a cam mechanism as movement converting means. In this cam mechanism, when the cam at an input side rotates relative to a cam at an output side, the cam at the input side axially moves to deflect a diaphragm spring in the same direction.
In the disk including the cam mechanism, a clutch plate which is connected to a friction facing is utilized as a support member for axially supporting the cam mechanism from the side opposite to the diaphragm spring. Therefore, if such structures are employed in such a type of disk that have especially large maximum torsion angle and/or torsion torque, the clutch plate may be plastically deformed by the reaction force caused by elastic deflection of the diaphragm spring, in which case the elastic force of the diaphragm spring is reduced and the disk can not effectively achieve the intended damping function.